Serena Williams has cast a spotlight on a side of domestic violence that is seldom seen - financial abuse.

The tennis champ is the star of a new short film highlighting the issue of men, or women, controlling their significant other with money, making it impossible for them to leave an abusive relationship.

On Thursday, Williams shared the clip with her almost 10 million Instagram followers.

(Instagram)

In the video, the 37-year-old is seen getting ready for a tennis match.

"If I limped on to the court, you’d notice,” her voiceover begins.

"If I had black eyes and broken bones, you’d notice. If I had marks on my arms and fear in my voice, you’d notice."

"It’d be easy to see that I need help, to know something was wrong. But what about the abuse you can’t see?"

(Instagram)

The video goes on to explain that financial abuse is “an invisible weapon” and that "it happens in 99 per cent of domestic violence cases, and it’s why many victims can’t just leave."